Tisdale: How Much of an Impact Does the Atlantic Multidecadal Oscillation Have on Arctic Sea Ice Extent?

Last week I asked Bob Tisdale to take a hard look at potential correlations between the AMO and Arctic sea ice extent, and he rose to the challenge – Anthony

Guest post by Bob Tisdale

This post presents reference graphs and a discussion of the effects of the Atlantic Multidecadal Oscillation on Arctic sea ice loss.

I was asked to show if and how well the Atlantic Multidecadal Oscillation (AMO) Index data correlates with the NSIDC Northern Hemisphere Sea Ice Extent data. I decided to carry the comparisons farther by also including high-latitude Northern Hemisphere temperature variables: land surface temperature anomalies, lower troposphere temperature anomalies, and a couple of sea surface temperature anomaly subsets. It should really come as no surprise that the high-latitude sea surface temperature anomalies in the Northern Hemisphere correlate best with Arctic sea ice extent anomalies. When the ice melts, it exposes the ocean surface. The surface temperature of the Arctic Ocean is warmer than ice so it will present a positive anomaly in areas where the sea ice hasn’t melted in the past. That is, where the freezing point of sea water serves as the base-period temperatures for anomalies, the surface temperature anomaly of any newly exposed water will be positive.

And I elected also to discuss the Atlantic Multidecadal Oscillation, its impacts, how it’s influenced by major El Niño events and how it’s misrepresented.

WHAT’S ALL THE HUBUB, BUB?

In a warming world, there are many expected responses. Among them, sea level will rise, glaciers will melt, and seasonal Arctic sea ice extent, area and mass will dwindle. Regardless of the source of the warming, those things will happen as global temperatures rise. I’m always amazed with the frenzy that accompanies a “new record” level in some variable, like the recent happenings with Arctic sea ice. While there is no proof mankind is responsible for the warming Arctic temperatures and loss of sea ice, there are, nonetheless, the typical baseless claims that we have caused it and we have to do to something about it.

The only place anthropogenic global warming definitely exists is in climate models. They must be FORCED by greenhouse gases in order to make the simulated oceans and atmosphere warm. The instrument temperature record shows the oceans and surface temperatures have warmed, but those records cannot be used to prove manmade global warming exists. On the other hand, as I have been showing for more that 3 ½ years, the instrument temperature record can be used to show that most if not all of the warming was caused by natural variables, and as a result, the observational data can be used to invalidate the climate models. If you’re not familiar with my work, refer to my recent post titled A Blog Memo to Kevin Trenberth – NCAR.

With that in mind, all of the following graphs show that high latitude surface temperatures have warmed and that sea ice extent has decreased, but there is no evidence that mankind is responsible for it. More on that later. And that brings us to…

POOR CORRELATION DOES NOT MEAN THERE IS A LACK OF CAUSATION

Of the variables we’ll compare to sea ice extent, high latitude land surface air temperatures correlate worst. Does this mean that warming land surface air temperatures don’t contribute to the variations in sea ice extent? No. Does it mean the loss of sea ice does not cause changes in land surface air temperatures? No. It simply means sea ice extent and land surface air temperatures are varying on different schedules to the many variables the impact them.

On the other hand, does the relatively high correlation between Arctic sea ice extent and Arctic sea surface temperature indicate the loss of sea ice is more closely related to the warming sea surface temperatures? No. The higher correlation, as noted earlier, is also caused by the fact that sea ice loss results in a greater surface area of open ocean where sea surface temperatures can be measured, and since that water is warmer than the freezing point of sea water, the anomalies in newly opened areas of ocean will have positive anomalies compared to the freezing point, which is the reference for the anomalies.

However, since water has more mass than air, a one deg warming of adjoining sea surface temperatures will have a greater impact on sea ice than a one deg warming of Arctic air. Therefore, since Arctic sea ice is exposed to the North Atlantic, the additional warming of the North Atlantic associated with the Atlantic Multidecadal Oscillation is a major contributor to Arctic sea ice loss regardless of the correlation between the two datasets.

DATA PRESENTATION

All monthly anomaly data in the sea ice comparisons have been standardized; that is, each dataset has been divided by its standard deviation. Since we’re using satellite-based Reynolds OI.v2 for sea surface temperature data, all of the graphs start in November 1981. All of the datasets end in August 2012. The temperature data have also been inverted to accommodate the inverse relationship between sea ice extent and temperature. Base years of 1982 to 2011 were used for anomalies to better align the sea ice data and temperature data when the latter were inverted—the exception is the AMO data. The title blocks of the graphs include the correlation coefficients of the NSIDC Northern Hemisphere sea ice extent and the respective temperature dataset. They have been determined with no lags between the datasets.

ATLANTIC MULTIDECADAL OSCILLATION INDEX

The NSIDC sea ice extent anomalies are compared to the inverted ESRL Atlantic Multidecadal Oscillation Index data in Figure 1. The correlation coefficient is poor at -0.57. There are some periods when the two curves align, and there are others when they don’t. Why doesn’t it correlate better? Arctic sea ice is impacted by North Atlantic sea surface temperatures along one exposure. Sea ice loss on the other side of the Arctic basin is impacted by other variables. Also, the Atlantic Multidecadal Oscillation represents the sea surface temperature anomalies of the entire North Atlantic, not just the portion that comes into contact with Arctic sea ice. We’ll discuss the impact of the Atlantic Multidecadal Oscillation on temperatures in the high latitudes of the Northern Hemisphere and on sea ice extent later in the post.

Figure 1

HIGH LATITUDE LAND SURFACE AIR TEMPERATURE AND LOWER TROPOSPHERE TEMPERATURE ANOMALIES

Figures 2 and 3 compare sea ice extent anomalies to GHCN-CAMS land surface air temperature (LSAT) anomalies and UAH lower troposphere temperature (TLT) anomalies, for the latitudes of 60N-90N. Like the AMO index data, some of the annual and seasonal variations in the curves align, and there are others that don’t. Keep in mind that lower troposphere temperature anomalies represent the temperatures at about 3,000 meters above sea level. Also, the TLT data does stretch across as far north as 85N over the Arctic Ocean, while the land surface air temperature data does not. The correlation coefficient for the land surface air temperature anomalies and sea ice extent is about -0.49, while for the lower troposphere temperatures it’s slightly higher at -0.57. Neither one is very good.

Figure 2

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Figure 3

HIGH LATITUDE SEA SURFACE TEMPERATURE ANOMALIES

As noted earlier, the best wiggle match presented in this post occurs between the high latitude (60N-90N) sea surface temperature anomalies and the Arctic sea ice extent, Figure 4. The correlation coefficient is -0.85. That’s pretty good for two climate-related variables.

Figure 4

For those interested in that hotspot in the Northwest Atlantic that’s been happening for the past few months, refer to Figure 5. It represents the sea surface temperature anomalies for that portion of the North Atlantic and Arctic Ocean, with the coordinates of 45N-90N, 80W-25W. The best we can say, though, is that the hotspot in the North Atlantic coincided with the high seasonal ice loss this year.

Figure 5

Referring back to our discussion of the Atlantic Multidecadal Oscillation, if we look at the sea surface temperature anomalies for the high latitudes of the North Atlantic (60N-90N, 80W-40E), we see a much improved correlation (-0.71 instead of -0.57 for the AMO). See Figure 6. And again, the North Atlantic directly impacts only one exposure of the Arctic sea ice. With that in mind, the correlation is very good.

Figure 6

NOTES ON THE ATLANTIC MULTIDECADAL OSCILLATION AS PRIMARY CAUSE OF HIGH LATITUDE WARMING AND SEA ICE LOSS

Note: The data is not standardized in the following graphs. They present temperature anomalies.

Many of the posts I’ve written about the Atlantic Multidecadal Oscillation (aka AMO) include a link to the RealClimate glossary about it, where they write:

A multidecadal (50-80 year timescale) pattern of North Atlantic ocean-atmosphere variability whose existence has been argued for based on statistical analyses of observational and proxy climate data, and coupled Atmosphere-Ocean General Circulation Model (“AOGCM”) simulations. This pattern is believed to describe some of the observed early 20th century (1920s-1930s) high-latitude Northern Hemisphere warming and some, but not all, of the high-latitude warming observed in the late 20th century. The term was introduced in a summary by Kerr (2000) of a study by Delworth and Mann (2000).

GISS climate models indicate the majority of the total warming of global surface temperatures over the past 30 years, about 85% (Figure 7), is in response to the warming of the oceans, so one might conclude the additional variability of the North Atlantic has played a major role in the warming of the high latitudes of the Northern Hemisphere. Figure 7 is from Chapter 8.11 of my book Who Turned on the Heat? The data presented in it is from the NASA Goddard Institute for Space Studies (GISS) ModelE Climate Simulations – Climate Simulations for 1880-2003 webpage, specifically Table 3. Those outputs are based on the GISS Model-E coupled general circulation model. They were presented in the Hansen et al (2007) paper Climate simulations for 1880-2003 with GISS modelE.

Figure 7

With that in mind, and referring back to the RealClimate glossary discussion, can we then assume that the multidecadal variability of the North Pacific could also be used to describe “some, but not all, of the high-latitude warming observed in the late 20th century”? Refer to Figure 8. Both datasets in it have been detrended and smoothed with 121-month running-average filters. The intent of Figure 8 is to show that there is a multidecadal signal in the North Pacific, north of 20N, that is not represented by the Pacific Decadal Oscillation index data—that the multidecadal variations in the North Pacific can run in and out of synch with the Atlantic Multidecadal Oscillation—and that the strength of the multidecadal signal in the North Pacific is almost as strong as in the North Atlantic. The multidecadal variations in the North Pacific are normally presented in abstract form as the Pacific Decadal Oscillation, so they are typically overlooked in discussions of the multidecadal variations in Northern Hemisphere land surface air temperatures.

Figure 8

The normal misconception, misinterpretation, misunderstanding, misrepresentation of the Atlantic Multidecadal Oscillation is that it is a form of natural variability that occurs on top of the manmade global warming of the rest of the oceans. The Wikipedia definition of the Atlantic Multidecadal Oscillation begins:

The Atlantic multidecadal oscillation (AMO) was identified by Schlesinger and Ramankutty in 1994.

The AMO signal is usually defined from the patterns of SST variability in the North Atlantic once any linear trend has been removed. This detrending is intended to remove the influence of greenhouse gas-induced global warming from the analysis.

There is no “influence of greenhouse gas-induced global warming” evident in the sea surface temperature records for the past 30 years. We’ve discussed and illustrated this in numerous posts here at Climate Observations over the past 3 ½ years. After the processes El Niño-Southern Oscillation, this was the primary topic of discussion of my book Who Turned on the Heat? – The Unsuspected Global Warming Culprit, El Niño-Southern Oscillation. Here’s an overview:

The South Atlantic-Indian-West Pacific dataset covers the ocean basins not represented by the East Pacific and North Atlantic. The sea surface temperature anomalies of the South Atlantic-Indian-West Pacific only warm during and in response to the strong El Niño events of 1986/87/88 and 1997/98. See Figure 9. There may also have been an upward shift in response to the 2009/10 El Niño but it’s a little early to tell. As you’ll note, the South Atlantic-Indian-West Pacific data cools between the major El Niño events. The trends are negative.

Figure 9

Why are there upward shifts in response to those major El Niño events? Because the South Atlantic-Indian-West Pacific sea surface temperature anomalies do not cool proportionally during the La Niña events that followed them. We can show this by detrending the South Atlantic-Indian-West Pacific data and comparing them to NINO3.4 sea surface temperature anomalies, which are a commonly used index that represents the frequency, strength and duration of ENSO events. Figure 10 is from the blog post here. If the South Atlantic-Indian-West Pacific data cooled proportionally during those La Niña events, its curve would be similar to the East Pacific data, which shows no warming in 30 years.

Figure 10

So far, we have found no evidence of an “influence of greenhouse gas-induced global warming” in the ocean basins that are outside of the North Atlantic. Would the “influence of greenhouse gas-induced global warming” exist only in the North Atlantic? That’s extremely unlikely. Therefore, we can dismiss the consensus opinion that the global oceans are warmed by anthropogenic greenhouse gases.

Let’s take a look at the North Atlantic data. As expected, it shows warming trends between the major El Niño events, Figure 11. But notice how the trend line for the latter period is located above the trend line for the earlier period. That means there was an upward shift in response to the 1997/98 El Niño event.

Figure 11

We can also detrend the North Atlantic sea surface temperature anomalies and compare them to scaled NINO3.4 data to illustrate the cause. The North Atlantic sea surface temperature anomalies also do not cool proportionally in response to the La Niña events that follow the major El Niño events. So the non-linear response of the North Atlantic (and the AMO) to ENSO is a significant portion of the additional warming of the North Atlantic and the subsequent natural sea ice loss in the Arctic.

Figure 12

SHAMELESS PLUG

I’ve referenced my recently published e-book (pdf) a number of times in this post. The book is about the phenomena called El Niño and La Niña and its long-term effects. It’s titled Who Turned on the Heat? with the subtitle The Unsuspected Global Warming Culprit, El Niño Southern Oscillation. I do not specifically discuss the loss of Arctic sea ice in the book, but as discussed in this post, those losses are primarily a response to the natural warming of the global oceans.

The book is intended for persons (with or without technical backgrounds) interested in learning about El Niño and La Niña events and in understanding the natural causes of the warming of our global oceans for the past 30 years. Because land surface air temperatures simply exaggerate the natural warming of the global oceans over annual and multidecadal time periods, the vast majority of the warming taking place on land is natural as well. The book is the product of years of research of the satellite-era sea surface temperature data that’s available to the public via the internet. It presents how the data accounts for its warming—and there are no indications the warming was caused by manmade greenhouse gases. None at all.

Since there is no evidence of a manmade component in the warming of the global oceans over the past 30 years, the natural additional warming of the sea surface temperature anomalies of the North Atlantic—above the natural warming of the sea surface temperatures for the rest of the global oceans—has been a major contributor to the natural loss of Arctic sea ice over the satellite era. Add to that the weather events that happen every couple of years and we can pretty much dismiss the hubbub over this year’s record low sea ice in the Arctic basin. Personally, I’d find it comical—if the desperation on the parts of AGW proponents wasn’t so evident. That makes it sad.

79 thoughts on “Tisdale: How Much of an Impact Does the Atlantic Multidecadal Oscillation Have on Arctic Sea Ice Extent?”

I have been meaning to ask a question. This is about as good a time as any.

With the really shallow angle of the Sun at high latitudes, radiant warming of the region is pretty low compare to the tropics. When sea-ice is lost, and the water is open to the sky, how fast is energy radiated to space as compared to when there is an insulating cover of ice? Does that have an impact on the overall energy budget? My gut feeling says it does, but that’s outside my field of knowledge.

“…That is, where the freezing point of sea water serves as the base-period temperatures for anomalies, the surface temperature anomaly of any newly exposed water will be positive….”

Positive temperature anomalies are often taken by climate “science” as indicating warming, when they actually represent more heat exposed to 4ºK deep space temperatures, instead. It’s like saying Denver must be gaining population because we counted more people in its bus stations this year than we did last year.

If some ocean areas have not warmed over the last 30 years then I assume this contradicts any argument that CO2 is acting globally on water. Since Antarctic ice extent is not decreasing, and looking at last 30 years slightly increasing, then this also indicates that globally ice is not declining as you would expect (if CO2 was thought to be the culprit). The simplistic idea (and so this is probably not in any pf the models!) is that the Arctic, being surrounded by land mass, will have more variability in ice extent due to land mass related parameters (blocking patterns?). Also, having ocean currents flushing through Bering and Greenland seas would also in my mind be the most obvious candidate for significant ice extent variations. When we have completed the next cycle of the AMO (around 2030?) , and have approx 50 years satellite data, then I think we can conclude with confidence whether Arctic ice extent is in significant decline. I would be a worried man if my income, and more importantly scientific reputation, was linked to the idea that CO2 is the major player. Luckily for me I don’t have any scientific reputation to worry about!

10yr @ 3 millimeter per year = 1.181102361 inches per decade
100yr @ 3 millimeter per year = 11.81102361 inches per century

Arctic and glacial melt is adding 3mm a year to rising oceans, according
to NOAA !

Satellites trace sea level change

By Jonathan Amos Science correspondent, BBC News, 24 September 2012

A major reassessment of 18 years of satellite observations has provided a new, more detailed view of sea-level change around the world.
Incorporating the data from a number of spacecraft, the study re-affirms that ocean waters globally are rising by just over 3mm/yr (emphasis added)

Andrew, there are two counter arguments offered. I’m not saying they are right, just that this is what is said.

The first is that there is stored heat someplace in the oceans. Pielke has argued forcefully that there is not and cannot be, but that is the argument – it is warming, and the warming is in the oceans, just below where its being measured. It has been thought of.

The second is that the models show Arctic and Antarctic ice behaving differently so the rise in the latter does not refute them. In addition, the Antarctic rise is relatively small, whereas the Arctic loss is large.

I am not persuaded that there is anything to worry about in the Arctic, but there are counters to the arguments you’re offering. The main issue is the length of the trend. We only have proper data of the same sort for the satellite era, and to splice this onto conjectures about the extent and depth of the last several hundred years does not seem any more legitimate than splicing modern temperature readings onto the hockey stick proxies.

We are however in the middle of a natural crucial experiment on Arctic ice. If it continues to decline for another 5-10 years at the same rate, we will know something quite unusual is going on. If the trend reverses and heads north again, we’ll be able to conclude for sure that AGW is dead in the water.

Nearly 3 years ago I wrote a short article (with one or two later additions) about some unusual aspects of the Arctic temperature and the relationship with the AMO.http://www.vukcevic.talktalk.net/NFC1.htm
It is easy to dismiss my observations, but then it is hardly likely to be understood what is going on there by just looking at the surface and ignore the rest.

“It is not until the warming of the Arctic, 1905–30, that the NAO winter index shows repeated positive values over a number of sequential years, corresponding to repeated northward fluxes of warmer air over the Nordic Seas during the winter. An analog repetition of southward fluxes of colder air during wintertime occurs during the cooling period in the 1960s. Concurrently, the temperature in the ocean surface layers was lower than normal during the warming event and higher than normal during the cooling event.”

“The August ice extent in the Eastern area has been more than halved over the past 80 yr. A similar meltback has not been observed since the temperature optimum during the eighteenth century. This retrospective comparison indicates accordingly that the recent reduction of the ice extent in the Eastern area is still within the variation range observed over the past 300 yr.”

Taurisano, A., Boggild, C.E. and Karlsen, H.G. 2004. A century of climate variability and climate gradients from coast to ice sheet in West Greenland. Geografiska Annaler 86A: 217-224.
“the temperature data show that a warming trend occurred in the Nuuk fjord during the first 50 years of the 1900s, followed by a cooling over the second part of the century, when the average annual temperatures decreased by approximately 1.5°C.” Coincident with this cooling trend there was also what they describe as “a remarkable increase in the number of snowfall days (+59 days)”

Climate variation in the European Arctic during the last 100 years Hanssen-Bauer, Inger, Norwegian Meteorological Institute, Co-Author Førland, Eirik J. (CliC International Project Office (CIPO) 21 June 2004)

“Analyses of climate series from the European Arctic show major inter-annual and inter-decadal variability, but no statistically significant long-term trend in annual mean temperature during the 20th century in this region. The temperature was generally increasing up to the 1930s, decreasing from the 1930s to the 1960s, and increasing from the 1960s to 2000. The temperature level in the 1990s was still lower than it was during the 1930s. In large parts of the European Arctic, annual precipitation has increased substantially during the last century.”

These days we sweat over whether the next satellite data point will be a positive or a negative anomaly, in relation to a norm which is based on the average of the last 33 years, to prove or disprove whether CO2 is cooking the planet.

in australia, this Reuters’ BoM story has suddenly appeared in just a single Fairfax newspaper in Sydney. mind you, every second para has a somewhat contradictory message:

25 Sept: SMH: Reuters: Chance of El Nino’s return ebbs, BoM says
Tropical Pacific Ocean temperatures indicating the onset of an El Nino have eased over the last two weeks, reducing the chance of the weather event emerging, the Australian Bureau of Meteorology said today…
Pacific Ocean temperatures had cooled in the last fortnight, while other indicators remained in neutral territory, it said…
Japan’s weather bureau said on September. 10 its climate models indicated the El Nino phenomenon was under way and there was a high chance it would last until the northern winter…http://www.smh.com.au/environment/climate-change/chance-of-el-ninos-return-ebbs-bom-says-20120925-26j01.html

meanwhile, further north in Brisbane, this Fairfax newspaper was reporting just yesterday that, because BoM was predicting El Nino, there was no need continue with the previous State Govt’s decision to keep the dam at 75% level (lobbied by the new State Govt when in Opposition). talk about confusing, especially for the thousands of locals who are still considering taking out a class action lawsuit over the degree of flooding they believe was caused last year because the Dam was allowed to stay full when heavy rains had been forecast by BoM. the fact this dam is so huge, it holds enough water for years, if not decades, according to some so-called experts, only makes these mixed messages from BoM more worrying:

24 Sept: Brisbane Times: Daniel Hurst: Situation normal: outlook makes Wivenhoe release unlikely
Brisbane’s Wivenhoe Dam is unlikely to be drawn down to 75 per cent capacity as a precaution for the wet season, after the Newman government received an expert briefing that widespread flooding was unlikely this summer.
According to a Bureau of Meteorology briefing to the state cabinet today, southeast Queensland has a 50 per cent chance of exceeding the median rainfall from October to December.
This means the region is likely to be on track for average rainfall.
BOM Queensland regional director Rob Webb told cabinet the last two years were wetter than average, but this summer the state could expect typical periodic flood events but not as widespread as in recent years…
Global conditions indicated neutral conditions, bordering on El Nino. This contrasts with La Nina conditions when widespread flooding is more likely.
Wivenhoe Dam is currently at 99 per cent of its full drinking water supply level. In addition to the space devoted to drinking water storage, the dam has space for holding water in the event of a flood…http://www.brisbanetimes.com.au/queensland/situation-normal-outlook-makes-wivenhoe-release-unlikely-20120924-26gux.html

Bob Tisdale reckons
While there is no proof mankind is responsible for the warming Arctic temperatures and loss of sea ice
———–
Cobblers! It’s not about logical proof. It’s about a scientific theory, a prediction that arises from that theory, the observation that is consistent with the prediction and the conclusion that this represents evidence to support the theory.

I’m a scientist at the National Centre for Atmospheric Science (NCAS) in the UK. My main area of research is the variability and predictability of sea ice cover. I think this is a fascinating area of research and I’m glad Bod Tisdale has written about this in this blog.

However, I am concerned that the lack of any mention of peer reviewed literature in this makes it seem like this is not an area of research in the climate community and that we only talk about the influence of man on the climate. Rather the contrary, in the decadal prediction and predictability community (of which NCAS is a contributing organisation) we focus on the “internal” or “natural” variability in the climate system of which the AMO is major component. In this sense, predictability refers to memory in the earth system which could be utilised for forecasting. It has long been known that every climate variable evolves with a signal composed of an internal variability part and externally forced part (human influenced, solar etc.). The question is how to separate the two.

In the analysis of Day et al. (2012) we find that about 5-30% of the decline in September sea ice extent since the 70s is due to the AMO leaving the rest unaccounted for.

Whilst I think that Bob’s analysis is interesting, I have a couple of concerns.

Though the correlation analysis indicates that the AMO and sea ice extent are related, it does not, as the article states, imply that anthropogenic climate change has not had an influence. For example there is evidence that the AMO may be modified by changes in the concentrations of man-made aerosols e.g. Booth et al. 2012 (Nature).

My other concern is that the period of analysis here only uses sea ice/AMO data from a 30 year period. The AMO has a period of 65-80 years which makes it hard to see if they are varying on the same time scales, the trend over 30 years could simply be coincidental. Also both time series in Fig 1 have an ambient trend. This means that to calculate significance of correlation you have to take into account the autocorrelation somehow, which doesn’t appear to have been stated.

At a recent conference in Bergen, Martin Miles and others presented work looking at historical sea ice observations and AMO proxies back to the 1600s which looked pretty convincing, though I don’t expect this will be published for some months.

Therefore, we can dismiss the consensus opinion that the global oceans are warmed by anthropogenic greenhouse gases.
———
Does this mean that Bob believes the oceans are warmed by natural green house gases and are not warmed by green house gases produced by man?

we find that about 5-30% of the decline in September sea ice extent since the 70s is due to the AMO

Jonathan Day, I suspect you may be missing a positive feedback in your percentages. When the Arctic warms it slows the movement of warm tropical air to the north pole due to a smaller temperature gradient. Of course, this also means the areas between the tropics and the north pole also warms. In addition, this also leads to warming of the land and oceans areas. Hence, you have a warmer flow from the great lakes to the north Atlantic, warmer river flows into the arctic and a warmer gulf stream. All of these factors enhance the AMO warming effect.

I believe it is possible that as much as half of AGW may be the result of the combination of these events. Given other natural variability, like Bob’s ENSO hypothesis, and it’s not unreasonable that absolutely no warming comes from changes in the atmospheric GHG content.

Jonathan Day (September 25, 2012 at 4:20 am) wrote:
“I’m a scientist at the National Centre for Atmospheric Science (NCAS) in the UK. My main area of research is the variability and predictability of sea ice cover. I think this is a fascinating area of research and I’m glad Bod Tisdale has written about this in this blog.
[…]
At a recent conference in Bergen, Martin Miles and others presented work looking at historical sea ice observations and AMO proxies back to the 1600s which looked pretty convincing, though I don’t expect this will be published for some months.”

Jonathan Day says:
September 25, 2012 at 4:20 am
…………….
Hi Dr. Day
Thanks for the comments. Read your article, seen your video, we don’t need to agree about causes and consequences to be able to exchange our views.
You mentioned natural variability, peer review, earth system memory, proxies and the AMO reconstruction to 1600.
I have looked at all of those, natural variability in the North Atlantic, read number of peer-reviewed papers including Dr. Mann’s AMO, found that the system memory is approximately 15 years, and used a geomagnetic proxy for reconstructing the (de-trended) AMO, albeit only from 1700.
What did I get?
Comparing to the Mann’s and Gray’s reconstructions my result is of higher resolution and more in agreement with the accepted AMO data sets:http://www.vukcevic.talktalk.net/AMO-recon.htm
in more detail for 1880-2011http://www.vukcevic.talktalk.net/GSC1.htm
But would it pass peer review?
I doubt it, for simple reasons: done by an outsider, doesn’t require a single reference except two or three widely available data sets, and further more the physics of it could be clearly stated at the back of a postcard.
Interested?
I doubt that too, but your comment is welcome.

LazyTeenager says: “Cobblers! It’s not about logical proof. It’s about a scientific theory, a prediction that arises from that theory, the observation that is consistent with the prediction and the conclusion that this represents evidence to support the theory.”

Cobblers? Thanks for the laugh, LazyTeenager.

You’ve been around here long enough to understand the bases for my comment. The post even goes on the explain it. The sea surface temperature record contradicts the hypothesis (not theory) of anthropogenic global warming. Therefore, the hypothesis is flawed. As they used to say long before your time, “Back to the old drawing board”. That applies to AGW. It’s time for them to revise it and put an end to the alarmist nonsense.

If the oceans are rising, then why do the British Admiralty charts from surveys 200-300 years ago, drawn by the likes of Cook, Bligh, Vancouver and Flinders show no significant change in sea levels over that time?

After all, peoples lives worldwide depend on these charts. If global sea level rise was ongoing and measurable, why is it not shown on the charts? These charts do show lat and long corrections.

Jonathan Day: Thank you for your comment on this thread. However, I believe you’ve overlooked the part of the post beyond the correlation of sea ice extent with temperature variables. That was really the thrust of this post. The correlation graphs were provided as references.

There is no evidence of an anthropogenic component in the satellite-era sea surface temperature records. This tends to negate any attempts by the climate science community and anthropogenic global warming proponents to attribute the reduced sea ice extent to manmade greenhouse gases and other anthropogenic forcings–until such time they can reconcile those deficiencies with the simulated oceans in the models.

michel says: “…We are however in the middle of a natural crucial experiment on Arctic ice. If it continues to decline for another 5-10 years at the same rate, we will know something quite unusual is going on. If the trend reverses and heads north again, we’ll be able to conclude for sure that AGW is dead in the water.”

I don’t think either statement is true. Natural cycles could be totally responsible for ice decline/increase. Thirty years of satellite observations is a very, very short time relative to the Earth’s known climate cycles, ice ages, etc. And, of course, that “hidden heat” is a story made up to account for why the Earth isn’t currently heating. Hiding heat is like trying to smuggle a lit candle out of a church in a bucket of ice.

For example, let’s look at the base periods. If the grid we’re looking at includes sea ice during some Januarys but open ocean during others, like some areas of the North Atlantic, then the January climatology would be the average of the measured sea surface temperatures when there was open ocean and the freezing point of water (1.8 deg C) for the years when there was ice present.

Andrew says: “…The simplistic idea (and so this is probably not in any of the models!) is that the Arctic, being surrounded by land mass, will have more variability in ice extent due to land mass related parameters (blocking patterns?)….”

True. Also, Arctic maximum ice extent (area) is largely constrained by geography. At points of constraint (shorlines), additional ice has no place to go except downward, where it’s hard to measure. Thus variability in extent tends to be limited on the upside, unrestrained on the downside.

Jason says: “But would you mind putting the air temperature on the graphs?”

Land surface air temperature records end at the shoreline, so how would anyone know what the temperature of the air is over the Arctic sea ice? TLT is measured at 3000 meters above sea level so you can’t use it either.

Why are we always told to look at the minimum? If we chose instead to look at the maximum, we’d conclude that we’re almost back to the 30y average. It’s just more cherry-picking.

If we look at the ice extent data and fitler out the annual variation we get a true picture of what has been happening since 2007… and it’s a sea change.

The plumetting melting stopped in 2007. There was a significant [recovery] and a regression, that still leaves a net regain of ice extent. When did you last see that info presented anywhere?

Also there is a return to the cyclic behaviour that was typical before the plunge.
The key difference since 2007 is much larger annual swing in ice extent (probably due to thinner ice coverage) . Only looking at one end of these large swings and saying “OMG , it’s worse than we thought” is stupid or dishonest.

It is no more legitimate than to look at the max and claim all is back to normal.

The skeptic world seems to have been conned into following this obsession with the ice minimum which , while dramatic, is not representative of Arctic climate.

Bob says: “There is no evidence of an anthropogenic component in the satellite-era sea surface temperature records. This tends to negate any attempts by the climate science community and anthropogenic global warming proponents to attribute the reduced sea ice extent to manmade greenhouse gases and other anthropogenic forcings”

So what does the “trend” that you remove in your detrending operation represent?
What was the magnitude of the trend you removed?

That is a significant temperature gradient, you cannot just arbitrarily remove it just because Excel has a “detrend” button.

Jason says:
September 25, 2012 at 7:57 am
……………
Either ice melts from underneath (note the melt marks) or an oversize penguin climbed at the top (this is Antarctic iceberg) and the iceberg lost its balance.

It is important to note that is it ONLY “land” surface temperatures in the LOWER Arctic that are increasing over the past 60 years of increasing CO2 levels: that is, surface temperatures over the Arctic land areas between 65 and 75 north latitudes are increasing.

Air temperatures at 80 north latitude since 1959 (that same time frame) in the summertime (the only time when sunshine is present to be absorbed) have been steady, and slightly more negative the past few years as CO2 has gotten even higher.

But, since ALL plant life over ALL the earth is now growing 13% to 27% faster, higher, and thicker due to that same increase in CO2, it is reasonable to attribute that increase in temperature to the increased albedo due to that CO2-inspired tundra and forest tree growth.

More CO2 -> more growth across the land areas in the Arctic -> more energy absorbed in those areas -> higher air temperature in the land-covered Arctic regions.

But, no change in sea surface temperature, no change in air temperature further north at 80 north. And, of course, there is essentially no sea ice below 80 north at time of minimum extents. (See DMI temperatures at 80 north, sea ice page, WUWT)

LazyTeenager says:
September 25, 2012 at 4:14 am
—-
I had a theory that you were going to say that.

The problem with your claim is that while the observations do partially match what was predicted by one of the many global warming models. The same observation is better explained by other theories that do not rely on the magical gas.

I was most intrigued by the areas in several of your graphs that show “divergence”, and was wondering where the proof was for the text that implied a “causation”. . . . . particularly a causation associated with volcanic eruptions. Since I believe that Willis E. hit the nail on the head when he postulated that equatorial tropical storms “boil off”/ dissipate/ regulate excess heat absorbed by the oceans, I wonder if you could correlate the timing of these apparent “divergence” periods to an upswing in major tropical storms for those oceans that “lost” heat, and a downward trend in tropical storms for those oceans that retained the heat. I also wonder about the actual movement of large masses of “heated” water transporting this heat. If the transport occurs on to landfall, can it not be concluded that many “landfall” events during any given tropical storm season have the net effect of “removing” heat from the oceans, and wouldn’t that be the major difference between tropical heat transport in the Atlantic vs the Pacific?

The other thing to keep in mind about Arctic temperatures is that the volcanoes appear to have twice the impact here as the global values (this might be a coincidence or it might be polar amplification showing up).

Mount Pinatubo and El Chichon appear to show up in the temperature record and when combined with the AMO, we get a much greater correlation.

ENSO, AMO, Volcanoes, Solar and CO2 Model versus UAH North Pole Ocean temperatures (note the ENSO does not reach significance in this model but I left it in anyway).

Could there be another factor warmng the ArcticOceans? Such as a change in the subduction of magma near Alaka’s “rim of fire” Kurile island chain? Would the possible rise of magma closer to the undersea side of the seabed, like a tiny fire on the underside of a tea kettle, possibly cause a slow rise in the surface temperatures?
See http://en.wikipedia.org/wiki/Submarine_volcano

P. Solar says: “That is a significant temperature gradient, you cannot just arbitrarily remove it just because Excel has a ‘detrend’ button.”

I did not arbitrarily remove it. I detrended the data to show why a portion of the trend exists. If the North Atlantic responded linearly to ENSO, the offset between the trend lines in Figure 11 would not exist.

For the South Atlantic-Indian-West Pacific data, the only reason there is any trend at all is because that dataset fails to cool proportionally during the La Nina events. Without those offsets, the South Atlantic-Indian-West Pacific data actually cools.

MarkW says: “How can this possibly be real science. Bob Tisdale is not an officially accredited climate scientist.”

Ah, but my posts pass most of the requirements for the “new” peer review being promoted by Richard Muller: “In science, peer review means you give talks to the public. You send your papers to colleagues around the world. That’s what I did. Before I wrote my op-ed, we put all of our papers available on the Web.”

My blog posts are read by colleagues around the world. I make my papers available on the web. Yup. That’s what I do. I just haven’t given talks to the public. Maybe I should. I could charge the venues $100k per presentation just like Al.

Don V: In looking at Willis’s post here…https://wattsupwiththat.com/2010/12/29/prediction-is-hard-especially-of-the-future/
…he was not stating that volcanic eruptions did not impact surface temperatures; he was noting how the models overestimated the response. The two graphs with detrended sea surface temperatures and scaled NINO3.4 data above are simply another way to show the actual changes caused by the volcanoes.

Dr. Tisdale
I will try one last time. I have a hard time reading any volume off computer screens. Therefore I want to buy a hard copy of your book if available. Can you please tell me if one is or will be available.

RobW – It would be possible to buy Bob’s pdf and get it printed professionally, though understandably it adds quite a bit to the price. (If Bob were to get a batch done, it would work out slightly cheaper per book, but then you’d have to add postage, of course.) For example, InkyLittleFingers in the UK can do 50 (A5) pages in B/W for a shade under 20 UKP, delivered to the UK. Or, teach yourself basic bookbinding and make one at home – I’ve seen some quite nice examples.

I agree re screens, btw, they’re ok to ‘scan’ but wearing for a good read. One of the ‘electronic books’ might also be a practical solution, if you can find one that suits you. A friend of mine has a Kindle, which looks okay to my aging eyes – certainly better than a screen (LCD or CRT).

Bob, thanks for your cordial response. Forgive me for being unclear in my comment. I wasn’t doubting your attribution of the divergences to major volcanic activity. Your hypothesis seems plausible, so I agree with you. Instead I was questioning whether you or anyone else can (or has) provided any other evidence to support this hypothesis with data (ie. increase in SO2, increase in particulate, decrease/increase in storm activity etc.). And has anyone used that data then, to successfully and accurately “predict” a near future climate trend such as is suggested by the “divergences” you note? For expample, did the volcanic activity recently from Iceland produce sufficient particulate to affect a long term climate trend? Did anyone measure and determine what the “threshold” level of particulate needs to be to have a predictive value? Also, what would you consider to be evidence to disprove this hypothesis?

More importantly, where you have provided an alternative hypothesis as to the reason for the “divergence” as being non-cooling of the Southern Oceans during a La Nina period, I was wondering whether tropical storm activity, specifically the tracking of whether large tropical storm make landfall or stay over the ocean, might give insight into where the energy harvested from the ocean was transported and where it ended up. Since the evidence to support the hypothesis that water, (liquid, air born aerosol, gas, and in the case of the poles, as a solid) is by far the largest transporter (and source/sink) of heat throughout the livable spaces on our planet, I was also just wondering whether anyone had ever attempted to “track” the major movements of heat energy as it has moved with the water around the planet (large oceanic storms, warm and cold ocean currents, El Nino events etc.)

For instance, has anyone ever attempted to measure and quantitate the increase in radiative energy transfer into space that surely must occur at the tops of thunderstorms as phase change occurs and gas turns to vapor turns to liquid, (and even ice!)

“…Cobblers! It’s not about logical proof. It’s about a scientific theory, a prediction that arises from that theory, the observation that is consistent with the prediction and the conclusion that this represents evidence to support the theory…”

Theory: That CO2 causes GLOBAL warming.

The prediction: Here is what the IPCC AR4 SPM says, page 15: “…Sea ice is projected to shrink in BOTH the Arctic and Antarctic under all SRES scenarios…”

Observation: The Antarctic sea ice has seen it’s highest three values in the past 5 years – 2007, 2012, 2010 (since satellite observation started), and the Antarctic sea ice anomaly has been ABOVE zero since 1992 – about 20 years.

That kinda shoots out your last part: “…the conclusion that this represents evidence to support the theory…”

So let’s move on to your next diatribe:

LazyTeenager said (September 25, 2012 at 4:29 am)

“…Does this mean that Bob believes the oceans are warmed by natural green house gases and are not warmed by green house gases produced by man?…”

Please, tell us exactly how much of the current 392.41 parts per MILLION of global CO2, as measured at Mauna Loa (http://co2now.org) is determined to have been made by man?

Common measurements use the C12/C13 ratio, and even there, you wouldn’t be able to tell the difference between coal used for heating, and natural coal seam fires (some of which have burned for decades). From Wiki: “…Across the world, thousands of underground coal fires are burning at any given moment. The problem is most acute in industrializing, coal-rich nations such as China. Global coal fire emission are estimated to include 40 tons of mercury going into the atmosphere annually, and three percent of the world’s annual CO2 emissions…”

So, to paraphrase your question, then: Does this mean that you believe the oceans are warmed by emissions from coal fired power plants and are not warmed by green house gases from global coal fire emissions?

I have been meaning to ask a question. This is about as good a time as any.

With the really shallow angle of the Sun at high latitudes, radiant warming of the region is pretty low compare to the tropics. When sea-ice is lost, and the water is open to the sky, how fast is energy radiated to space as compared to when there is an insulating cover of ice? Does that have an impact on the overall energy budget? My gut feeling says it does, but that’s outside my field of knowledge.

Your observation is correct, most strikingly for the period of the time at minimum sea ice extent in mid-September for the Arctic. In today’s Arctic, minimum sea ice extent is approximately 4 million km^2, which corresponds to a “cap” over the pole extending from 90 north (the pole) to 80 north latitude. Minimum sea ice extent occurs n mid-September, very, very close to the equinox when the sun is over the horizon only 12 hours per day.

A typical value used by Curry and others for heat loss due to evaporation is 105 to 117 watts/meter square.

At the MAXIMUM solar angle of 10 degrees at noon at the equinox at the southernmost boundary of the average sea ice extents, approximately 23 percent of the solar radiation is reflected, and 75% absorbed. Sounds like a lot, except, at 10 degrees solar incidence, the air mass that solar ray must transmit is 6-11 times what it is at the equator (depending on turbity, etc.) A time-weighted “average” solar angle is between 2-3 degrees (6:00 AM to 8:00 AM, 4:00 PM to 6:00 PM) with some 85% reflected, and 8:00 AM to 10:00 AM (2:00 PM to 4:00 PM) of 3-6 degrees when some 65% of the incident solar energy is reflected from rough waters, etc. Under cloudy conditions, approximately 65% of available solar energy is reflected from the high altitude and mid-altitude accompanying clouds typical of stormy conditions and higher wind conditions.

Therefore, at the region where minimum Arctic sea ice extents occur, at the time of minimum sea ice extent, you are correct: When additional sea ice is melted in today’s Arctic Ocean, significantly more energy is lost from the newly exposed ocean surface by evaporation than is absorbed from the newly exposed ocean from the sun.

Thus, you will typically find that maximum Arctic sea ice extents are higher in the winters immediately AFTER a low summer minimum, and a lower sea ice maximum occurs in those winters after a high sea ice minimum. Polar amplification (a positive feedback from higher ocean temperatures in the Arctic causing more sea ice melting from season-to-following-season, does not occur.

I know that you disclaim paleo knowledge, but I would like to ask you again or someone else, to consider researching a paper/blog on what the Atlantic ocean temperature response would have been to the closing of the Isthmus of Panama about 2.5 million years ago that stopped direct communication between the Pacific and the Atlantic and initiated the current ice age. The premise seems to be that if the Pacific El Ninio had continued to have direct communication with the Atlantic at the point of Panama, that the Atlantic would have had a different response to temperature influences than today.

Now we have a long standing Ice Age and periodic glaciations (100,000 yrs) and Interglacial periods (20,000 yrs) that is said in other papers to last as long as there is a continent on either pole. Sorry for the lack of links, but this information comes from my earliest forays into the AGU Paleo Oceanagraphic papers and Paleo Climate papers of approximately 6 – 10 years ago and I didn’t collect links, for most papers I was reading hard copy that I didn’t keep.

Bob, are you or anyone else up to this puzzle? I think it would be quite enlightening.

Bob says: “I did not arbitrarily remove it. I detrended the data to show why a portion of the trend exists.”

That’s just saying it’s not arbitrary because it fits your argument. I detrend it because I like the result.

You are not answering my question. What was the magnitude of the trend you removed (you do not even seem to know), and what does it represent physically. If you cannot attibute physical meaning to the trend you are removing, you can not attibute physical meaning the what remains.

You are suggesting ENSO produces step changes (which I’m inclined to give some credance to ) so why are you removing a linear trend?

“…he [Willis] was not stating that volcanic eruptions did not impact surface temperatures; he was noting how the models overestimated the response. The two graphs with detrended sea surface temperatures and scaled NINO3.4 data above are simply another way to show the actual changes caused by the volcanoes.
”
No, he was very much stating that the impact of volcanoes could not be seen if you did not where it was to start with. ie there is no visible effect on climate. Your very confident claims that these discrepancies can be attributed to volcanoes is without foundation. You are just assuming that is the case not proving it.
As I pointed out last time you posted all this , the huge deviation you are attributing to Mt Pinatubo is to a large extent due to the fact that YOU have cooled the planet by removing the trend.

I think you have demonstrated an important point of how ENSO can , by cooling the oceans, warm surface temperatures. This can be argued without detrending.

I ask again, how big is this trend and what do you attribute it to physically?

RobW, thanks for the title, there’s no Dr. in front of my last name. Only my first name Bob.

My apologies, but due to the costs, I have no plans to produce hardcopy versions of my book. That does not keep you from buying a copy in pdf form and having one printed. However, please look into the costs of printing a 550+page color document. They are extremely high

Don V says: “Instead I was questioning whether you or anyone else can (or has) provided any other evidence to support this hypothesis with data (ie. increase in SO2, increase in particulate, decrease/increase in storm activity etc.).”

Policy Guy: I hope someone else on this thread can respond to your paleo questions. It’s likely the wrong thread to find someone, though. Hopefully, there will be a post on the subject soon where you can find someone who may have investigated it.

regarding RACookPE1978 says:
September 25, 2012 at 8:13 pm
===================================
Thank you for the post. Some more thoughts to consider. Antarctica sea ice is at lower latitudes then artic sea ice. As such it is reflecting more insolation. Additionally from Sept on, as we enter the SH spring and summer, the earth moves ever closer to the sun, until at max the earth is recieving seven percent more insolation then during the NH summer max. So SH sea ice recieves both more direct and more intense solar energy.

P. Solar, you must’ve got up on the wrong side of the bed because it appears you’re simply arguing for argument’s sake. I was in a good mood this morning. Past tense.

I have explained the processes that cause the trend in numerous posts. You’ve read those posts and commented on the threads. You state now that you give credence to ENSO causing the step changes, which means you have read the earlier posts and understood them. With that in mind, I do not understand your need to belabor this. If you want detailed explanations of the processes that cause the shifts and hence the long-term trend included in every post I write about the subject along with every graph that details every possible question you might have, it’s not going to happen. My book includes more than 380 illustrations. Which ones should I chose in anticipation of your question de jour, P. Solar?

Of course I know what the trends are for the datasets that I’ve presented detrended in this post. You very well understand that I had to determine the trends in order to detrend the data. I’ve presented graphs of the data with trend lines in past posts. You’ve read those posts. I can’t include every graph in every post simply because you might think I need to provide more detail in every post. If you insist on knowing the trend for the South Atlantic-Indian-West Pacific data, it’s about 0.093 deg C/decade:

We appear to have a difference of opinion on Willis’s post. Nothing new there. If you now want me to perform regression analysis with an ENSO index and aerosol optical thickness data to explain the dips and rebounds in the sea surface temperature data in the early 80s and 90s with every post I create, it’s not going to happen. But if you like, feel free to do it on your own. There are a couple of gridded AOD datasets available on the KNMI Climate Explorer if you really need to investigate the relationships for the individual ocean basins. Good luck.

Why do I include the detrended graphs in the post, P. Solar? It’s not just to cause you distress. I can see quite clearly that the South Atlantic-Indian-West Pacific dataset linked above does not respond proportionally to El Nino and La Nina events. Maybe you can see what’s obvious too, but there are others who have in the past stated that the graph simply shows a long-term warming trend with a volcanic aerosol component and an ENSO signal that’s responding linearly to El Nino and La Nina events. The detrended graph counters that argument because it shows without a doubt that the data does not respond to El Nino and La Nina events proportionally.

Bob. If I upset you by my phrasing of questions about El Nino etc on a blog last week, it was not my intent to do so. There were 2 main points. With each event (which I will not name a cycle) the global SST seems to increase. Like several people, I asked why it does not seem to decrease. From whece the added energy? Perhaps the sampling period is too short to get a proper pattern yet. I also mentioned Australia’s BOM doing work from islands to the north of Australia, some of which are in water too shallow for Argo floats. I refer you to a map which might have sites in deep enough water, but might not for some. The region appears a popular place to start the description of an El Nino event. From memory, there is another current network to the west of this, but don’t rely on that. See http://www.bom.gov.au/oceanography/tides/MAPS/pac.shtml

Doesn’t make sense: Even the fastest sailing ship could barely make that time – take, for example, the tea clipper ships from south China ports to England. They took advantage of the currents (staying out of head currents and staying (as best as possible) in stern currents), winds, most direct route, etc The Cutty Sark, for example, was built to shorten “world records” of 2-1/2 months, and most ships were half that fast at 7 – 8 knots. A random ocean current “floating along” naturally will be much, much slower in net speed.

However, it should be possible to study ship transit times around the Cape Horn to determine Antarctic currents and winds during the 1700’s and 1800’s. There might be information hidden in those travel times.

RACookPE1978 says:
September 27, 2012 at 7:10 am
……
I thought as much, since an ordinary ‘convicts’ ship took about 3 months.
What I think has happen, someone on the English south coast, where debris are washed out, found the bottle read message and seeing it is from 4 year old, traveled at some later stage to Australia and threw into sea there.